Summary

Among 579 autopsy cases of hepatocellular carcinoma (HCC), 55 cases (9.4%) exhibited a sarcomatous appearance. The incidence of HCC with a sarcomatous appearance has been increasing over the past 17 years. A sarcomatous appearance was found in 20 out of 335 autopsy cases of HCC (5.9%) during the 12 years from 1969 to 1980, and in 35 out of 244 autopsy cases of HCC (14.3%) during the last 6 years, when effective anticancer therapies, such as the one-shot injection of anticancer agents into the hepatic artery (one-shot therapy) and transcatheter arterial embolization (TAE), have become popular. A sarcomatous appearance was found in 20.9% of the cases undergoing anticancer therapy and in 4.2% of the cases not undergoing anticancer therapy. Among the various anticancer therapies, the sarcomatous appearance was most frequent (27.6%) in cases with repeated TAE. Thus, a close relationship between the sarcomatous appearance in HCC and anticancer therapies was suggested. Regarding the development of the sarcomatous appearance, we presume that it may be caused by the pyenotypic change of HCC cells caused by anticancer therapy, or that a number of factors, including anticancer therapy, may accelerate the proliferation of the sarcomatous cells existing in the original tumor as one of the histological components. In order to clarify the true nature of sarcomatous lesions in HCC, further histological and biological studies are required.